If you’re new to owning an AR-15, you’ve likely been in the situation where you’ve either just built or bought your rifle, only to realize that you still need an optic. Simply put, your choice of optic plays a crucial role in determining your build’s efficacy in your intended role.
Newcomers often assume that choosing one is an easy task, at least until they see just how many options there are. There is a plethora of optics that pair well with the AR-15, and they each come with their own distinct advantages.
The sheer variety of options can be daunting, but if you know what to look for in an optic, you won’t have any trouble picking the right one for your rifle.
Understanding AR-15 Optics
Optics are, easily, one of the most important accessories one can add to a rifle, offering far more advantages than standard iron sights. Instead of having to line up your sights, so long as your optic is zeroed properly, you simply need to put your reticle on target. Still, it’s important to recognize that not all optics are the same. Like we mentioned above, there are a lot of optics that pair well with the AR-15 and they each come with their own inherent benefits. Reflex sights and 1x prism scopes are incredibly agile, while variable power optics such as LPVOs and MPVOs offer more precision at longer ranges.
Choosing one can be difficult but narrowing down the right one is much easier when you take your intended use into consideration. Is your rifle going to be used for recreation, competition, duty, or hunting? Different optics cater to different applications and knowing how you plan to use your rifle will simplify the selection process.
While there are hundreds of options to choose from, just about every optic can falls into one of three categories: variable power optics, reflex sights, and prism scopes.
Variable Power Optics
Variable power optics are incredibly popular for applications requiring an extra modicum of long-range precision. These rifle scopes are available in several different magnification ranges, but for AR-15s, you’ll find that LPVOs and MPVOs pair particularly well with 5.56 AR-15 builds.
LPVOs
Low-Power Variable Optics, or LPVOs, are a versatile rifle scope that’s generally offered with either a 1-6x, 1-8x, or a 1-10x magnification range. LPVOs have become incredibly popular for their adaptability across close- and long-range applications. At 1x magnification, they offer a wide field of view and fast target acquisition capabilities, making them nearly as effective as reflex sights. And for long-range use, they can quickly be magnified to provide a better picture of the target.
Part of what makes LPVOs so effective is their reticle systems. Depending on the model you look at, these reticles can have many elements that are suitable for both close- and medium- to long-range use. For instance, optics like the Primary Arms SLx® 1-6x24mm SFP Rifle Scope come equipped with the ACSS® NOVA® reticle system, which uses a unique fiber wire reticle construction, that has a Red Dot Bright™ center dot as well as crosshairs with MIL-based subtensions or BDC holds (only on NOVA 5.56 scopes). For FFP optics with etched reticles, when zoomed out to 1x magnification, they often feature an illuminated center point, with more complex ranging elements becoming visible when magnified.
MPVOs
Medium-Power Variable Optics, better known as MPVOs, offer more in terms of medium- to long-range use, with 2-10x, 4-16x, and 3-18x being some of the more common magnification ranges they’re offered in.
By design, they aren’t the most effective choice for close quarters use, but it’s important to recognize that they aren’t designed for such applications. They provide an extra degree of precision when shooting distant targets, making them more useful for precision shooting disciplines and hunting. They can still be used for close-range engagements when at low magnification, but they aren’t necessarily the quickest—though this can be overcome by using an offset optic.
There’s a lot to cover when discussing variable power optics, so we recommend checking out our guide, “How Does a Rifle Scope Work?” to get a more in-depth look on the intricacies of these optics.
Reflex Sights
Reflex sights are some of the most popular optics available for the AR-15. Prioritizing speed, they offer enhanced target acquisition capabilities as well as a wider FOV. While it’s generally encouraged to aim with both eyes open, regardless of what optic you’re using, it’s much easier to do so with reflex sights, and it allows you to place your full focus on the target rather than the reticle itself.
As such, these optics are commonly used for just about all applications ranging from recreation to more intensive competitive and duty use. Just like with variable power optics, there’s a lot to unpack with reflex sights, as the term “reflex sight” encompasses multiple optics—red dot sights, open-emitter optics, and holographic sights are all reflex sights.
Types of Reflex Sights
Red dot sights are usually the first optic that comes to mind when discussing reflex sights. They feature a minimalistic design, consisting of an optic tube and two lenses. Even further, they’re available in a wide range of sizes including full-size red dots which are larger and generally offer more durability, and micro red dots which are much smaller and are often the lightest options.
Open-emitter reflex sights function and perform very similarly to red dot sights, with their main distinction being their construction. Much like their name suggests, these optics feature an open-emitter design, using only one lens as opposed to two. As such, they’re generally lighter than red dot sights since they don’t require as much material to produce, and they have a wider field of view thanks to their open design. Still, their design does expose the emitter diode, making it susceptible to occlusion from environmental debris.
Last are holographic sights, the most unique of the three. Rather than reflecting light off one surface, light from the emitter diode is bounced off several surfaces, creating a floating reticle between the optic’s lenses. With this design, these optics have very little parallax and are less prone to astigmatic distortion, plus, they generally offer excellent night vision performance. However, their unique designs make them more expensive than other reflex sights, and there’s also less variety since such optics are currently only produced by EOTech and Vortex Optics.
Regardless of which one you look at, they all can be exceptionally useful, and depending on the model, they can even have unique reticles instead of just the standard dot. Some popular options like circle dot reticles offer better ranging capabilities, with others like the ACSS® CQB reticle system offer some added utility with its precise center chevron and BDC elements. With such reticles, you can easily use a red dot for both close and medium-range applications, which we highlight in our Red Dot Sight Range Guide for AR-15s.
Red Dot Magnifiers
If you plan to use a reflex sight, you may want to consider running a red dot magnifier alongside it. As their name suggests, they’re used to magnify the reticle and target image, allowing you to make more precise shots on targets at farther distances. Magnifiers are available in a wide range of magnification levels, with some common ones being 3x, 5x, and 6x.
Additionally, since they mount behind your reflex sight, they’re typically attached to a hinging mount that can flip to the side when not in use, allowing you to quickly switch from magnified and non-magnified use. Also, magnifiers are fairly brand-agnostic—so long as the mount heights match, you can mix and match brands with no issues in most cases. As such, there are a lot of great red dot magnifier combos for the AR-15.
Prism Scopes
Prism scopes are a more unique optic variant that effectively blends design elements from both reflex sights and variable power optics. Most notably, they retain the compact form-factor of reflex sights, while also having etched reticles and magnification (at times) like rifle scopes. We highlight these optics at length in our guide, “The Advantages of Using Prism Scopes”, but below is a summary to get you up to speed on them.
One of the standout advantages offered by prism scopes is their reticle systems. By using etched reticles, these optics are capable of housing complex reticle designs complete with BDC holds, crosshairs, and finer aiming points like center chevrons. Not only are their reticle elements much finer and crisper than reflex sight reticles, but they also don’t have any risk of becoming distorted if you have astigmatism, since the reticle is a physical element and not just a projection. Like reflex sights, the reticle can be illuminated for greater visibility, but you can still use them if they aren’t.
As we mentioned above, prism scopes are available in both magnified and non-magnified configurations. 1x prism scopes are basically as agile as reflex sights, plus, they can even be compatible with magnifiers too. This isn’t true of all prism scopes, but optics like the Primary Arms Optics GLx® and SLx® 1x MicroPrism™ Scopes were designed to be compatible with magnifiers, allowing you to easily switch between magnified and non-magnified use. If you’d rather have fixed magnification but still want a fast optic, 2x and 3x prisms fall within the sweet spot range that allows you to keep both eyes open while still being magnified.
Magnified options are more akin to variable power optics, but they’re limited in their adaptability since they come with a fixed magnification level instead of an adjustable one. This locks you in to only one magnification level. While this is beneficial for engaging distant targets, you won’t have as much leeway as you would with a variable power optic, making offset optics a solid choice. Select optics can come with 12 O’clock mounts that are compatible with various mini-reflex sights, and you can always opt for an offset optic as well. It’s also important to note that prism scopes with any magnification higher than 1x aren’t compatible with magnifiers. Using one can create a blurry sight picture and excess scope shadow, making offset optics the best way to switch to a non-magnified option.
Conclusion
Choosing an optic for your AR-15 is a critical decision that can drastically affect the overall utility and capabilities of your rifle. As such, it’s paramount that you understand how each option performs, while also taking your needs and preferences into consideration
Reflex sights and 1x prism scopes offer the most in terms of agility, providing a wide field of view and a precise point of reference for aim. Meanwhile, variable power optics like MPVOs excel in long-range applications, as they provide more targeting information and are available in higher magnification ranges. Lastly, LPVOs and magnified reflex sights/1x prism scopes can effectively bridge the gap between close and long-range optics, making them a solid pick for general purpose builds.
Although each optic can be a more than effective choice, ultimately, the best one is the one that best aligns with your needs and preferences. If you choose a red dot sight, we recommend checking out our guide, “How to mount a Red Dot on an AR-15”. It goes in-depth on all that you’ll need to know when mounting various types of red dots.
